Which of the following facts determines how often a nonroot bridge or switch sends an STP Hello BPDU message?

Which of the following facts determines how often a nonroot bridge or switch sends an STP Hello BPDU message?

• The Hello timer as configured on that switch.
• The Hello timer as configured on the root switch.
• It is always every 2 seconds.
• The switch reacts to BPDUs received from the root switch by sending another BPDU 2 seconds after receiving the root BPDU.

Explanation: Nonroot switches forward Hellos received from the root; the root sends these Hellos based on the root’s configured Hello timer.